The present invention relates to an evaporator in which a header inlet tank chamber and a header outlet tank chamber are integrally formed together by a plurality of laminated tubes.
FIGS. 1 to 3 show a conventional evaporator of this kind. As shown in FIGS. 1 and 2, an evaporator 100 mainly includes laminated tubes 101, corrugated fins 102 each disposed between the adjacent tubes 101, a refrigerant inlet pipe 103 connected to one end side of the laminated tubes 101, and a refrigerant outlet pipe 104 connected to the other end side of the laminated tubes 101.
Each tube 101 includes a pair of tube plates 101a and 101a which are opposed to and connected to each other. As shown in FIG. 3, the tube 101 is provided therein with a U-shaped refrigerant passage 110, an inlet header chamber 111 which is in communication with one end of the refrigerant passage 110, and an outlet header chamber 112 which is in communication with the other end of the refrigerant passage 110. The inlet header chambers 111 of the adjacent tubes 101 are in communication with each other through a communication hole 113. An assembly of the inlet header chambers 111 forms a header inlet tank chamber 114. The refrigerant inlet pipe 103 is connected to the header inlet tank chamber 114.
As shown in FIG. 3, the outlet header chambers 112 of the adjacent tubes 101 are in communication with each other through a communication hole 115. An assembly of the outlet header chambers 112 forms a header outlet tank chamber 116. The refrigerant outlet pipe 104 is connected to the header outlet tank chamber 116.
As shown in FIG. 3, a pair of left and right arc refrigerant holding projections is provided at a boundary between the inlet header chamber 111 and the refrigerant passage 110. Semi-arc refrigerant storing spaces 118 are formed on the refrigerant holding projections 117. Refrigerant which flows into the inlet header chamber 111 is temporarily stored in the refrigerant storing space 118. A first communication passage 119 is formed between lowermost ends of the pair of refrigerant holding projections 117. An uppermost end of one of the refrigerant holding projections 117 is connected to a plate edge 120, and a second communication passage 121 is formed between the plate edge 120 and an uppermost end of the other refrigerant holding projection 117. A pair of refrigerant holding projections 117 is similarly formed at the boundary between the outlet header chamber 112 and the refrigerant passage 110. The same elements are designated with the same symbols, and explanation thereof will be omitted.
Flow of refrigerant in the evaporator 100 will be explained. Refrigerant which flows from the refrigerant inlet pipe 103 flows into the header inlet tank chamber 114, and flows into the refrigerant passage 110 from the inlet header chamber 111 of each tube 101. Then, the refrigerant flows along the U-shaped passage, during which process, the refrigerant exchanges heat with fluid existing outside. The refrigerant flowing through the refrigerant passage 110 flows into the header outlet tank chamber 116 from the outlet header chamber 112 of each tube 101, and merges with another refrigerant which has circulated through another refrigerant passage 110 of another tube 101 and then flows out from the refrigerant outlet pipe 104.
During this flowing process of the refrigerant, liquid phase refrigerant which enters into each inlet header chamber 111 enters the refrigerant storing space 118 on the refrigerant holding projection 117. The liquid phase refrigerant which has entered the refrigerant storing space 118 drops into the refrigerant passage 110 from the lowermost first communication passage 119. If the flowing amount is greater than the dropping amount, the liquid phase refrigerant is gradually stored therein. If the liquid phase refrigerant in the refrigerant storing space 118 overflows, the liquid phase refrigerant drops into the refrigerant passage 110 from the second communication passage 121. Gas phase refrigerant which has entered into the inlet header chamber 111 flows into the refrigerant passage 110 from the second communication passage 121.
Therefore, when an amount of flowing refrigerant is enough and liquid phase refrigerant always overflows from the refrigerant storing space 118 of each tube 101, the refrigerant is distributed to the refrigerant passages 110 of the tubes 101 substantially equally.